Jay S. Schneider, Ph.D.
Thomas Jefferson University
In an NIEHS-funded study, researchers found that exposure to lead affected associative learning and memory in rats. The researchers also observed differences in males and females, and varied effects from exposure during different developmental windows, suggesting a complex interaction between sex, developmental windows of exposure, and effects on memory.
The researchers exposed both male and female rats to three environmentally relevant levels of lead during three developmental periods. They categorized overlapping developmental periods as perinatal, or gestation to postnatal day 21; early postnatal, or postnatal days 1-21; and late postnatal, or postnatal days 1-55. They then used a test that required coordination of the medial prefrontal cortex and hippocampal brain regions to assess the effects of lead on learning and memory.
In female rats, researchers saw significantly impaired memory recall with early and late postnatal exposure to lead but not with perinatal exposure. In contrast, male rats only had significant recall deficits with exposure during the perinatal period.
This work highlights the complex interactions between lead exposure and other factors on development. In addition to adversely affecting the formation and recall of memories, damage to the prefrontal cortex and hippocampus may also underlie emotional and behavioral dysregulation frequently seen in children exposed to lead.
Citation: Anderson DW, Mettil W, Schneider JS. 2016. Effects of low level lead exposure on associative learning and memory in the rat: influences of sex and developmental timing of exposure. Toxicol Lett 246:57-64.